The present invention relates to benzofuran derivatives which have phosphodiesterase (PDE) IV inhibitory activity and which are useful as a therapeutic agent for inflammatory allergic diseases such as bronchial asthma, allergic rhinitis and nephritis; autoimmune diseases such as rheumatism, multiple sclerosis, Crohn""s diseases, psoriasis and systemic lupus erythematosus; diseases of the central nervous system such as depression, amnesia and dementia; organopathy associated with ischemic reflux caused by cardiac failure, shock and cerebrovascular disease, and the like; insulin-resistant diabetes; wounds; AIDS; and the like.
Heretofore, it is known that the functions of numerous hormones and neurotransmitters are expressed by an increase in the concentration of adenosine 3xe2x80x2,5xe2x80x2-cyclic monophosphate (cAMP) or guanosine 3xe2x80x2,5xe2x80x2-cyclic monophosphate (cGMP), both of which are the secondary messengers in cells. The cellular concentrations of cAMP and cGMP are controlled by the generation and decomposition thereof, and their decomposition is carried out by PDE. Therefore, when PDE is inhibited, the concentrations of these secondary cellular messengers increase. Up to the present, 7 kinds of PDE isozymes have been found, and the isozyme-selective PDE inhibitors are expected to exhibit pharmaceutical effect based on their physiological significance and distribution in vivo [TiPS, 11, 150 (1990), ibid., 12, 19 (1991)].
It is known that the activation of inflammatory leukocytes can be suppressed by increasing the concentration of the cellular cAMP. The extraordinary activation of leukocytes causes secretion of inflammatory cytokines such as tumor necrosis factor (TNF), and expression of the cellular adhesion molecules such as intercellular adhesion molecules (ICAM), followed by cellular infiltration [J. Mol. Cell. Cardiol., 12 (Suppl. II), S61 (1989)].
It is known that the contraction of a respiratory smooth muscle can be suppressed by increasing the concentration of the cellular cAMP (T. J. Torphy in Directions for New Anti-Asthma Drugs, eds S. R. O""Donell and C. G. A. Persson, 1988, 37, Birkhauser-Verlag). The extraordinary contraction of a respiratory smooth muscle is a main symptom of bronchial asthma. Infiltration of inflammatory-leukocytes such as neutrophils is observed in lesions of organopathy associated with ischemic reflux such as myocardial ischemia. It has been found that the type IV PDE (PDE IV) mainly participates in the decomposition of cAMP in these inflammatory cells and tracheal smooth muscle cells. Therefore, the inhibitors selective for PDE IV are expected to have therapeutic and/or preventive effect on inflammatory diseases, respiratory obstructive diseases, and ischemic diseases.
Further, the PDE IV inhibitors are expected to prevent the progress and spread of the inflammatory reaction transmitted by inflammatory cytokines such as TNFxcex1 and interleukin (IL)-8, because the PDE IV inhibitors suppress the secretion of these cytokines by increasing the concentration of cAMP. For example, TNFxcex1 is reported to be a factor of insulin-resistant diabetes because it declines the phosphorylating mechanism of insulin receptors in muscle and fat cells [J. Clin. Invest., 94, 1543 (1994)]. Similarly, it is suggested that the PDE IV inhibitors may be useful for autoimmune diseases such as rheumatoid arthritis, multiple sclerosis, and Crohn""s disease because TNFxcex1 participates in the onset and progress of these diseases [Nature Medicine, 1, 211 (1995) and ibid., 1, 244 (1995)].
WO97/20833 discloses benzofurancarboxamide derivatives having PDE IV inhibitory activity, but none of compounds having substituted piperazinylcarbonyl bound at the 2-position of the benzofuran ring are specifically disclosed.
WO96/36624 discloses benzofuran derivatives having PDE IV inhibitory activity.
However, the conventional PDE IV inhibitors have a problem of induction of vomiting [TiPS, 18, 164 (1997)].
A novel and useful PDE IV inhibitor is expected to have prophylactic or therapeutic effects on a wide variety of diseases. An object of the present invention is to provide benzofuran derivatives having a superior anti-inflammatory activity and causing no vomiting.
The present invention relates to benzofuran derivatives represented by following formula (I): 
wherein R1 represents lower alkyl, R2 represents hydrogen or substituted or unsubstituted lower alkyl, R3, R4, R5 and R6 independently represent hydrogen or lower alkyl, X represents CH2 or Cxe2x95x90O, and Y represents CH2 or NH, or pharmaceutically acceptable salts thereof.
Hereinafter, the compounds represented by the general formula (I) are referred to as Compound (I). The same applies to the compounds of other formula numbers.
In addition, the present invention relates to a therapeutic agent for inflammatory allergic diseases, which comprises Compound (I) or a pharmaceutically acceptable salt thereof as an active ingredient.
Further, the present invention relates to a method for treating inflammatory allergic diseases, which comprises administering an effective amount of Compound (I) or a pharmaceutically acceptable salt thereof.
Furthermore, the present invention relates to a use of Compound (I) or a pharmaceutically acceptable salt thereof for the preparation of a pharmaceutical composition which is useful for the treatment of inflammatory allergic diseases.
The pharmaceutically acceptable acid addition salt of Compound (I) includes inorganic acid salts such as hydrochloride, sulfate, nitrate and phosphate, and organic acid salts such as acetate, maleate, fumarate and citrate.
In the definitions of the groups in formula (I), the lower alkyl includes straight-chain or branched C1 to C8 alkyl groups such as methyl, ethyl,.propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl and octyl.
The substituted lower alkyl has the same or different 1 to 3 substituents such as hydroxy and substituted or unsubstituted lower alkoxy. The alkyl moiety of the lower alkoxy has the same meaning as the lower alkyl defined above, and the substituted lower alkoxy has the same or different 1 to 3 substituents such as hydroxy.
Among Compound (I), preferred compounds are Compound (I) wherein R2 is substituted or unsubstituted lower alkyl, and specifically preferred compounds are Compound (I) wherein R2 is lower alkyl or hydroxy-substituted lower alkyl.
Among Compound (I), preferred compounds are Compound (I) wherein X is CH2, and Y is CH2; or x is Cxe2x95x90O, and Y is CH2 or NH.
A process for producing Compound (I) is described below.
Process: Compound (I) can be produced according to the following processes.
Process 1 
(In the formulae, R1 has the same meaning as defined above, and R7 represents lower alkyl.)
In the above formulae, the lower alkyl represented by R7 has the same meaning as the lower alkyl defined above.
Compound (III) can be produced by subjecting Compound (II) to formylation. Compound (II) as the starting material can be synthesized according to a method described in Bull. Soc. Chim. Fr., 2355 (1973) or a similar method thereto.
Specifically, Compound (III) can be obtained by reacting Compound (II) in an inert solvent with 1 equivalent to a large excess of dichloromethyl methyl ether in the presence of 1 equivalent to an excess of an acid for 5 minutes to 48 hours at a temperature between xe2x88x9250xc2x0 C. and the boiling point of the solvent used.
Examples of the acid are methanesulfonic acid, hydrochloric acid, sulfuric acid, trifluoroacetic acid, boron trifluoride, aluminum chloride, stannic chloride, titanium tetrachloride, zinc chloride and ferric chloride, among which titanium tetrachloride is preferable.
Examples of the inert solvent are tetrahydrofuran (THF), dioxane, diethyl ether, ethylene glycol, triethylene glycol, glime, diglime, dichloromethane, chloroform, benzene and toluene, among which halogenated hydrocarbons such as dichloromethane and chloroform are preferable.
Processes 2 to 4 
(In the formulae, R1 and R7 have the same meanings as defined above.)
Process 2: Compound (IV) is obtained by oxidation of Compound (III). For oxidation of the aldehyde to its corresponding carboxylic acid, a method for oxidation with metal oxidizing agents (permanganate, chromic acid) and a method for oxidation with halides (halogenous acid, hypohalogenous acid, salts thereof) are known (see Jikken Kagaku Koza, 4th edition, 23 (1990), Maruzen). Hereinafter, an example of reaction by sodium chlorite (J. Org. Chem., 51, 567 (1986)) is described. Compound (IV) can be obtained by reacting Compound (III) with 1 equivalent to an excess of sodium chlorite at a temperature between 0xc2x0 C. and 30xc2x0 C. for 1 to 48 hours in the presence of 1 equivalent to an excess of sulfamic acid in aqueous acetic acid.
Process 3: Compound (VI) can be obtained by dehydration condensation reaction between Compound (IV) and Amine Compound (V). Compound (IV) is converted into its corresponding acid chloride by treating it with 1 equivalent to a large excess of thionyl chloride in an inert solvent, if necessary in the presence of a catalytic amount to an excess of a base, for 30 minutes to 10 hours at a temperature between room temperature and the boiling point of the solvent used, and said acid chloride is reacted without isolation with 1 equivalent to an excess of Amine Compound (V) in an inert solvent in the presence of 1 equivalent to an excess of a base for 5 minutes to 10 hours at a temperature between xe2x88x9280xc2x0 C. and the boiling point of the solvent used, whereby Compound (VI) can be obtained. If necessary, said acid chloride as a reaction intermediate may be isolated. Alternatively, mixed acid anhydrides corresponding to Compound (IV) may be produced by using ethyl chloroformate etc. in place of thionyl chloride in the reaction described above, followed by reaction with Amine Compound (V), whereby Compound (VI) can also be obtained.
Examples of the base are sodium hydroxide, potassium hydroxide, sodium methoxide, potassium ethoxide, sodium hydride, potassium hydride, butyl lithium, lithium diisopropylamide (LDA), potassium tert-butoxide, triethylamine, diisopropylethylamine, tributylamine, dicyclohexylmethylamine, N-methylmorpholine, N-methylpiperidine, diazabicycloundecene (DBU) and diazabicyclononene(DBN).
Examples of the inert solvent are THF, dioxane, diethyl ether, ethylene glycol, triethylene glycol, glime, diglime, methanol, ethanol, butanol, isopropanol, dichloromethane, chloroform, benzene, toluene, dimethylformamide (DMF) and dimethyl sulfoxide (DMSO).
Process 4: Compound (X-a) can be obtained by reacting Compound (VI) in an inert solvent with 1 equivalent to a large excess of an aqueous alkali solution for 5 minutes to 10 hours at a temperature between 0xc2x0 C. and the boiling point of the solvent used.
Examples of the aqueous alkali solution are aqueous solutions of sodium hydroxide or potassium hydroxide, and examples of the inert solvent are dioxane, methanol and THF.
Processes 5 to 9 
(in the formulae, R1 and R7 have the same meanings as defined above.)
Process 5: Compound (VIII) can be obtained by addition reaction of Compound (III) obtained in Process 1 and Compound (VII). Compound (VII) is treated in an inert solvent with 1 equivalent to a large excess of a base for 5 minutes to 10 hours at a temperature between xe2x88x92100xc2x0 C. and the boiling point of the solvent used, and then reacted with Compound (III) for 5 minutes to 30 hours at a temperature between xe2x88x92100xc2x0 C. and the boiling point of the solvent used, whereby Compound (VIII) can be obtained. Compound (VII) can be synthesized by a method described in e.g. Handbook for Experimental Methods in Organic Synthesis (compiled by Society of Synthetic Organic Chemistry, Japan), page 577, 1990.
Examples of the base are sodium hydroxide, potassium hydroxide, sodium methoxide, potassium ethoxide, sodium hydride, potassium hydride, butyl lithium, LDA, potassium tert-butoxide, triethylamine, diisopropylethylamine, tributylamine, dicyclohexylmethylamine, N-methylmorpholine, N-methylpiperidine, DBU and DBN.
Examples of the inert solvent are THF, dioxane, diethyl ether, ethylene glycol, triethylene glycol, glime, diglime, methanol, ethanol, butanol, isopropanol, dichloromethane, chloroform, benzene, toluene, DMF and DMSO.
Process 6: Compound (IX) can be obtained by reduction of Compound (VIII) with hydrosilane. The reduction of a hydroxyl group by a combination of hydrosilane and an acid is well-known (see Jikken Kagaku Koza, 4th edition, 26, 197 (1990), Maruzen), and this technique can be used. For example, Compound (VIII) is reacted with 1 equivalent to a large excess of hydrosilane in an inert solvent, more preferably in a halogen-type solvent such as dichloromethane, in the presence of 1 equivalent to an excess of an acid, more preferably in the presence of boron trifluoride for 5 minutes to 48 hours at a temperature between xe2x88x92100xc2x0 C. and the boiling point of the solvent used, whereby the desired compound (IX) can be obtained.
Examples of the inert solvent are THF, dioxane, diethyl ether, dichloromethane, chloroform, dichloroethane, DMF and DMSO.
Examples of the hydrosilane are triethylsilane, trichlorosilane, n-butylsilane, diphenylsilane, phenylsilane, dimethylphenylsilane, and triethoxysilane.
Examples of the acid are boron trifluoride, titanium tetrachloride, aluminum trichloride, zinc chloride and trifluoroacetic acid.
Process 7: Compound (X-b) can be obtained by treating Compound (IX) according to the same process as in Process 4 above.
Process 8: Compound (XI) can be obtained by reacting Compound (VIII) with 1 equivalent to an excess of an oxidizing agent in an inert solvent including water for 5 minutes to 72 hours at a temperature between 0xc2x0 C. and the boiling point of the solvent used.
Examples of the oxidizing agent are manganese dioxide, potassium permanganate, pyridinium chlorochromate (PCC) and pyridinium dichromate (PDC).
Examples of the inert solvent are THF, dioxane, diethyl ether, ethylene glycol, triethylene glycol, glime, diglime, acetone, methyl vinyl ketone, dichloromethane, chloroform, benzene, toluene, DMF and DMSO.
Process 9: Compound (X-c) can be obtained by treating Compound (XI) according to the same process as in Process 4 above. Process 10 [Production of Compound (I) wherein X is CH2 and Y is CH2; or X is Cxe2x95x90O and Y is NH or CH2]
(In the formulae, R1, R2, R3, R4, R5 and R6 have the same meanings as defined above, Xa represents CH2 or Cxe2x95x90O, and Ya represents CH2 or NH, provided that Ya is not NH when Xa is CH2.)
Compound (Ia) can be obtained by reacting Compound (X-a), (X-b) or (X-c) with Compound (A) in the presence of 1 equivalent to an excess of a condensation agent in an inert solvent at xe2x88x9280 to 50xc2x0 C. for 5 minutes to 30 hours. If necessary, 1 equivalent to an excess of N-hydroxysuccinimide, 1-hydroxybenzotriazole or 3-hydroxy-4-oxo-3,4-dihydro-1,2,3-benzotriazine may be added.
Examples of the condensation agent are dicyclohexyl carbodiimide, diisopropylcarbodiimide, N-ethyl-Nxe2x80x2-3-dimethylaminopropylcarbodiimide and a hydrochloride thereof, benzotriazol-1-yl-tris(dimethylamino)phosphonium hexafluorophosphate and diphenylphosphorylazide.
Examples of the inert solvent are THF, dioxane, diethyl ether, dichloromethane, chloroform, dichloroethane, DMF, DMSO and water.
Compound (A) is commercially available but may be obtained by synthesis. For example, Compound (A) wherein R2 is lower alkyl substituted with hydroxy can be synthesized by the following processes.
Processes 11 to 13 
(In the formulae, R3, R4, R5 and R6 have the same meanings as defined above, R8 represents a protective group for an amine, R9 represents lower alkylene, R10 represents lower alkyl, and W represents halogen.)
The protective group R8 for an amine includes triphenylmethyl, tert-butoxycarbonyl (Boc), benzyloxycarbonyl and 9-fluorenylmethyloxycarbonyl (Fmoc). The halogen includes a fluorine, chlorine, bromine and iodine atom. The lower alkylene represented by R9 includes straight-chain or branched C1 to C7 alkylene such as methylene, ethylene, propylene, butylene, pentylene and hexylene. The lower alkyl represented by R10 has the same meaning as defined above.
Process 11: Synthesis of Compound (D)
Compound (D) can be obtained by reacting Compound (B) with Compound (C) in an inert solvent in the presence of 1 equivalent to a large excess of a base for 5 minutes to 10 hours at a temperature between 0xc2x0 C. and the boiling point of the solvent used.
Examples of the base are sodium hydroxide, potassium hydroxide, sodium methoxide, potassium ethoxide, sodium hydride, potassium hydride, butyl lithium, LDA, potassium tert-butoxide, triethylamine, diisopropylethylamine, tributylamine, dicyclohexylmethylamine, N-methylmorpholine, N-methylpiperidine, DBU and DBN.
Examples of the inert solvent are THF, dioxane, diethyl ether, ethylene glycol, triethylene glycol, glime, diglime, methanol, ethanol, butanol, isopropanol, dichloromethane, chloroform, benzene, toluene, DMF and DMSO.
Compounds (B) and (C) are commercially available.
Process 12: Synthesis of Compound (E)
Compound (E) can be obtained by reducing Compound (D). Compound (E) can be obtained by treating Compound (D) in an inert solvent with 1 equivalent to a large excess of a reducing agent for 5 minutes to 10 hours at a temperature between 0xc2x0 C. and the boiling point of the solvent used.
Examples of the reducing agent are sodium borohydride, lithium borohydride, lithium aluminum hydride and diisobutylaluminum hydride.
Examples of the inert solvent are THF, dioxane, diethyl ether, ethylene glycol, triethylene glycol, glime, diglime, methanol, ethanol, butanol, isopropanol, dichloromethane, chloroform, benzene, toluene, DMF and DMSO.
Process 13: Synthesis of Compound (A-a)
Compound (A-a) can be obtained by subjecting Compound (E) to suitable de-protection conditions.
For example, when R8 is a protective group such as tert-butoxycarbonyl or triphenylmethyl capable of being eliminated under acidic conditions, the desired compound can be obtained by reacting Compound (E) in an inert solvent with 1 equivalent to a large excess of an acidic solution as the acid for 5 minutes to 10 hours at a temperature between 0xc2x0 C. and the boiling point of the solvent used.
Examples of the acidic solution are hydrochloric acid, solutions of hydrogen chloride in ethyl acetate or in dioxane, trifluoroacetic acid and acetic acid.
Examples of the inert solvent are THF, dioxane, diethyl ether, ethylene glycol, triethylene glycol, glime, diglime, methanol, ethanol, butanol, isopropanol, dichloromethane, chloroform, benzene, toluene, DMF and DMSO.
Further, Compound (A) wherein R2 is lower alkoxyalkyl substituted with hydroxy can also be synthesized according to the same method as described above.
Alternatively, Compound (I) can also be produced in the method described below.
Processes 14 and 15 [Production of Compound (I) wherein X is CH2 and Y is CH2; or X is Cxe2x95x90O and Y is NH or CH2]
(in the formulae, R1, R3, R4, R5, R6, Xa and Ya have the same meanings as defined above, Z represents halogen, and R2a represents the same groups other than hydrogen as those of R2 defined above.)
In the formulae, the halogen defined as Z includes the same halogen as defied above.
Process 14: Compound (Iaa) can be produced by reacting Compound (X-a), (X-b) or (X-c) with Compound (B) according to the same process as Process 10 described above.
Process 15: Compound (Iab) can be obtained by reacting Compound (Iaa) with Compound (F) in an inert solvent in the presence of 1 equivalent to a large excess of a base for 5 minutes to 10 hours at a temperature between 0xc2x0 C. and the boiling point of the solvent used.
Examples of the inert solvent are THF, dioxane, diethyl ether, acetone, methyl vinyl ketone, dichloromethane, chloroform, benzene, toluene, DMF and DMSO.
Examples of the base are sodium hydroxide, potassium hydroxide, sodium methoxide, potassium ethoxide, sodium hydride, potassium hydride, butyl lithium, LDA, potassium tert-butoxide, triethylamine, diisopropylethylamine, tributylamine, dicyclohexylmethylamine, N-methylmorpholine, N-methylpiperidine, DBU and DBN.
Processes 16 and 17 [Production of Compound (I) wherein X is CH2 and Y is NH]
(In the formulae, R1, R2, R3, R4, R5 and R6 have the same meanings as defined above.
Process 16: Compound (XII) can be produced by reacting Compound (III) with Compound (A) according to the same process as Process described above.
Process 17: Compound (Ib) can be obtained by reacting Compound (XII) with Compound (V) in an inert solvent for 5 minutes to 10 hours at a temperature between 0xc2x0 C. and the boiling point of the solvent used, followed by reducing the formed imine with 1 equivalent to a large excess of a reducing agent for 5 minutes to 10 hours at a temperature between 0xc2x0 C. and the boiling point of the solvent used.
Examples of the reducing agent are sodium borohydride, sodium cyanoborohydride, lithium aluminum hydride and diborane, and further, it is possible to use catalytic reduction with nickel, platinum and palladium carbon as the catalyst.
Examples of the inert solvent are dichloromethane, chloroform, dichloroethane, benzene, toluene, THF, dioxane, diethyl ether, methanol, ethanol, butanol, isopropanol, DMF, DMSO, acetic acid and water.
The intermediates and the desired compounds in the processes described above can be isolated and purified by subjecting them to separation and purification methods conventionally used in synthetic organic chemistry, such as filtration, extraction, washing, drying, concentration, recrystallization and various kinds of chromatography. The intermediates can also be subjected to subsequent reaction without being particularly purified.
When it is desired to obtain a salt of Compound (I), Compound (I) is dissolved or suspended in a suitable solvent, then an acid is added thereto, and the resulting salt may be isolated and purified.
Further, Compound (I) and pharmaceutically acceptable salts thereof can also exist in the form of adducts with water or various solvents, which are also within the scope of the present invention. Compound (I) may exist in the form of stereoisomers such as enantiomers and diastereomeric isomers, and the present invention encompasses these isomers as well as mixtures thereof.
Hereinafter, specific examples of Compound (I) obtained according to the present invention are shown in Table 1.
Hereinafter, the pharmacological activity of typical Compound (I) is described in more detail by reference to the experimental examples.
Human phosphodiesterase cDNA (HSPDE4A) was isolated from testicles. Its predicted amino acid sequence is identical with the sequence (HSPDE4A5) reported by Bolger, G. et al. (Mol. Cell. Biol., 6558 (1993)) except that 223 amino acids have been deleted from the N-terminal thereof. This recombinant protein was expressed by an E. coli expression plasmid and then purified. The PDE activity was measured in the following 2-step process according to the method of Kincaid, R. and Manganiello, V. [Method. Enzymol., 159, 457 (1988)]. The substrate used was [3H]cAMP (final concentration: 1 mmol/l), and the reaction was performed in a standard mixture containing N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (50 mmol/l, pH 7.2), MgCl2 (1 mmol/l) and soybean trypsin inhibitor (0.1 mg/ml). The reaction was initiated by adding the enzyme thereto, and the mixture was incubated at 30xc2x0 C. for 10 to 30 minutes. The reaction was quenched by hydrochloric acid, and the formed 5xe2x80x2-AMP was completely decomposed with 5xe2x80x2-nucleosidase. This sample was subjected to chromatography on DEAE-Sephadex A-25, and the eluted [3H]adenosine was counted with a scintillation counter. The test compound was added after dissolved (concentration: 1.7%) in DMSO.
The results are shown in Table 2.
All compounds showed a high inhibitory activity of 70% or more concentration of 10xe2x88x927 mol/l.
Lipopolysaccharides (LPS, Difco) were dissolved in phsysiological saline at a final concentration of 0.2 mg/ml and administered in a dose of 200 xcexcl/20 g body weight into tail veins of 5 to 6 animals/group (BALB/c male mice (7-week-old) (Nippon Charles River)), and after 1 hour, blood was collected from the eye ground and serum was separated therefrom. The test compound was a dissolved or suspended at a final concentration of 1 mg/ml in a 0.5% methyl cellulose solution/ and 90 minutes before administration of LPS, it was orally administered in a dose of 200 xcexcl/20 g body weight. The concentration of TNF xcex1 in the serum was determined by enzyme-linked immunosorbent assay.(ELISA). 4 mg/ml anti-mouse TNF xcex1 monoclonal antibody (Genzyme) diluted with phosphate buffered saline (PBS) was added in a volume of 50 xcexcl/well to a 96-well flat-bottom microtiter plate (Nunc Immunoplate xe2x80x9cMaxi Sorpxe2x80x9d, Nunc Ltd.), followed by coating thereof on each well at 4xc2x0 C. for 12 hours. Then, phosphate buffered saline containing 1% bovine serum albumin (BSA) (1% BSA-PBS) was added thereto in a volume of 200 xcexcl/well and the plates were left at room temperature for 1 hour to block non-specific binding. Thereafter, the plate was washed with phosphate buffered saline, and the test serum diluted 2-fold with 1% BSA-PBS was added in a volume of 100 xcexcl/well and left for 2 hours at room temperature. In addition, recombinant mouse TNF xcex1 (Genzyme) diluted with 1% BSA-PBS was treated in the same procedure and used as the standard. These plates were washed 3 times with PBS (0.05% Tween-PBS) containing 0.05% polyoxyethylene sorbitan monolaurate (Tween 20, Wako Ltd.) Then, biotin-labeled anti-mouse TNF xcex1 polyclonal antibody (Pharmingen) diluted at a concentration of 1 xcexcg/ml with 1% BSA-PBS was added thereto in a volume of 50 xcexcl/well, and the plates were left at room temperature for 1 hour, and washed 3 times with 0.05% Tween-PBS. Horseradish Peroxidase Avidin D (Vector) diluted 4000-fold with 1% BSA-PBS was added thereto in a volume of 100 xcexcl/well and the plates were left for 30 minutes at room temperature. Finally, these plates were washed 3 times with 0.05% Tween-PBS, and 3,3xe2x80x2,5,5xe2x80x2-tetramethylbenzidine was added thereto in a volume of 100 xcexcl/well, and upon coloration, the reaction was quenched by adding 100 xcexcl/well of 10% sulfuric acid to each well. The absorbance at 450 nm was measured. The concentration of TNF xcex1 in the serum was calculated from a calibration curve.
The ratio of inhibition of TNFxcex1 production by the test compound was determined according to the following equation:
Ratio of inhibition(%)=(Axe2x88x92B)/Axe2x80x83xe2x80x83(Equation)
A: Concentration of TNF xcex1 in the control.
B: Concentration of TNF xcex1 in the sample in the presence of the test compound.
The concentration of TNF xcex1 in the control indicates the concentration in the absence of the test compound (a 0.5% methyl cellulose solution alone).
The comparative compounds used were 7-methoxy-4-[1-oxo-2-(4-pyridyl)ethyl]-spiro[2,3-dihydrobenzofuran-2,1xe2x80x2-cyclopentane].hydrochloride (referred to hereinafter as Compound P, JP-A 8-836624, Example 100) shown in formula (P): 
and 2-benzoyl-4-(3,5-dichloro-4-pyridyl)carbamoyl-7-methoxybenzofuran (referred to hereinafter as Compound Q, JP-A 8-534708, Example 35) shown in formula (Q): 
The results are shown in Table 3.
It is evident from Table 3 that as compared with Compounds P and Q which showed a high inhibitory activity on production of TNF xcex1, Compound (I) exhibited an equivalent inhibitory activity.
Male Sunkus murinus weighing about 60 g, 5 to 15 animals/group, were used in the test According to the method of Matsuki et al. (Japan J. Pharmacol., 48, 303 (1988)), each Sunkus animal was isolated and left in a wire-netting cage (15 cm widthxc3x9721 cm lengthxc3x9715 cm height). Each test compound was suspended in physiological saline containing 0.5% Tween 80 and then intraperitoneally (i.p.) administered into each animal in a dose of 10 xcexcl/g. After the test compound was administered, the animals were observed for 1 hour, and the frequency of vomiting was determined. The results were expressed in the number of animals with vomiting/the number of tested animals in the group given the test compound.
Compounds P and Q were used as the comparative compounds.
The results are shown in Table 4.
As shown above, all Compounds (I) of the present invention did not permit vomiting as opposed to comparative Compound P which though having a high inhibitory activity on production of TNF xcex1, caused vomiting as a side effect. Compound (I) is a compound having a high inhibitory activity on production of TNF xcex1 and simultaneously realizing the separation of vomiting as a side effect.
Further, Compound (I) has an amide structure containing a piperazine ring at the 2-position of the benzofuran skeleton and can be converted into a pharmaceutically acceptable acid addition salt. Taking it into consideration that the water solubility of comparative Compound Q is as very low as 1 xcexcg/ml or less, Compound (I) which by conversion into an acid addition salt, can drastically be improved with respect to water solubility is a compound which is also physically improved. For example, Compound 1 upon conversion into monohydrochloride becomes dissolved in water at a ratio of 7.4 xcexcg/ml.
Although Compound (I) or pharmaceutically acceptable salts thereof can also be administered as they are, it is usually desirable to provide them in the form of various pharmaceutical preparations. Such pharmaceutical preparations may be used for animals and humans.
The pharmaceutical preparations according to the present invention may contain Compound (I) or a pharmaceutically acceptable salt thereof as an active ingredient, alone or as a mixture with other therapeutically effective components. Further, such pharmaceutical preparations are produced by any means which are well-known in the technical field of pharmaceutics after mixing the active ingredient with one or more pharmaceutically acceptable carriers.
It is desired to use the administration route which is the most effective in therapy such as oral administration and parenteral administration which includes intrabuccal, intratracheal, intrarectal, subcutaneous, intramuscular and intravenous administration.
The administration form includes sprays, capsules, tablets, granules, syrups, emulsions, suppositories, injections, ointments and tapes.
Liquid preparations such as emulsions and syrups, which are suitable for oral administration, can be produced using water, sugars such as sucrose, sorbitol and fructose, glycols such as polyethylene glycol and propylene glycol, oils such as sesame oil, olive oil and soybean oil, preservatives such as p-hydroxybenzoate and flavors such as strawberry flavor and peppermint. Capsules, tablets, powder and granules can be produced using excipients such as lactose, glucose, sucrose and mannitol, disintegrators such as starch and sodium alginate, lubricants such as magnesium stearate and talc, binders such as polyvinyl alcohol, hydroxypropyl cellulose and gelatin, surfactants such as fatty acid esters, and plasticizers such as glycerin.
Preparations suitable for parenteral administration comprise a sterilized aqueous agent containing the active compound, which is preferably isotonic to the blood of a patient. For example, a solution for injection is prepared using a carrier such as a salt solution, a glucose solution or a mixture of a saline solution and a glucose solution. Preparations for intrarectal administration are prepared using a carrier such as cacao fat, hydrogenated fat and hydrogenated carboxylic acid, and provided as suppositories. Sprays are prepared using an active compound itself or with a carrier which can disperse the active compound as fine particles to facilitate absorption without stimulating oral or respiratory mucosa. Examples of such carriers are lactose and glycerin. Preparations such as aerosol and dry powder can be used depending on the properties of the active compound and carriers used.
These parenteral preparations may also contain one or more auxiliary components selected from diluents, perfumes, preservatives, excipients, disintegrators, lubricants, binders, surfactants, and plasticizers, all of which are mentioned in the above oral preparations.
The effective dose and administration schedule of Compound (I) or a pharmaceutically acceptable salt thereof may vary depending on the form of administration, the age and body weight of a patient, and the type or degree of the disease to be treated, but usually, in the case of orally administration, the effective compound is administered in a dose of 0.01 mg to 1 g/adult/day, preferably 0.05 to 50 mg/adult/day, at one time or in several parts. In the case of parenteral administration such as intravenous administration, the effective compound is administered in a dose of 0.001 to 100 mg/adult/day, preferably 0.01 to 10 mg/adult/day, at one time or in several parts. However, these doses vary depending on the various conditions described above. Hereinafter, the Preparation Examples of the present invention are described.
After a finely ground active ingredient is dissolved in distilled water for injection, the solution is filtered and the filtrate is sterilized in an autoclave to give an injection.
A finely ground active component is mixed with powdered potato starch, lactose, magnesium stearate and polyvinyl alcohol, and then compressed to form tablets.
A finely ground active ingredient is mixed with powdered lactose and magnesium stearate, and the resulting mixture is charged into gelatin capsules to give capsules.